To test whether remote ischaemic conditioning (RIC) as adjuvant to standard of care (SOC) would prevent progression towards heart failure (HF) after ST-elevation myocardial infarction (STEMI). Single-centre parallel 1:1 randomized trial (computerized block-randomization, concealed allocation) to assess superiority of RIC (3 cycles of intermittent 5 min lower limb ischaemia) over SOC in consecutive STEMI patients (NCT02313961, clinical trials.gov). From 258 patients randomized to RIC or SOC, 9 and 4% were excluded because of unconfirmed diagnosis and previously unrecognized exclusion criteria, respectively. Combined primary outcome of cardiac mortality and hospitalization for HF was reduced in RIC compared with SOC (n = 231 and 217, respectively; HR = 0.35, 95% CI 0.15–0.78) as well as each outcome in isolation. No difference was found in serum troponin I levels between groups. Median and maximum follow-up time were 2.1 and 3.7 years, respectively. In-hospital HF (RR = 0.68, 95% CI 0.47–0.98), need for diuretics (RR = 0.68, 95% CI 0.48–0.97) and inotropes and/or intra-aortic balloon pump (RR = 0.17, 95% CI 0.04–0.76) were decreased in RIC. On planned 12 months follow-up echocardiography (n = 193 and 173 in RIC and SOC, respectively) ejection fraction (EF) recovery was enhanced in patients presenting with impaired left ventricular (LV) function (10% absolute difference in median EF compared with SOC; P < 0.001). In addition to previously reported improved myocardial salvage index and reduced infarct size RIC was shown beneficial in a combined hard clinical endpoint of cardiac mortality and hospitalization for HF. Improved EF recovery was also documented in patients with impaired LV function.